Abstract: A mobile herbicide applying machine adapted for ground traversing movement over a field planted with a row crop and having a frame, a blower mounted on the frame, a manifold mounted on the frame and connected to the blower, a cleaning conduit connected to the manifold having an air outlet directed substantially horizontally and laterally of the direction of ground traversing movement adjacent to the ground surface, a spraying conduit connected to the manifold resistively retractable on contact with an obstruction having an air outlet rearwardly of the outlet of the cleaning conduit directed obliquely downwardly against the ground surface, a proportioning valve mounted in the manifold for regulating the relative air flow from the cleaning and spraying conduits, a reservoir for liquid herbicide mounted on the frame, a herbicide nozzle mounted in the outlet of the spraying conduit, a pump for supplying herbicide from the reservoir to the nozzle, and a power drive mechanism connected to the blower and the pump.